01961nas a2200193   4500008004100000245014800041210006900189260000800258300001400266490000700280520122900287100001901516700002301535700001701558700002701575700002001602700002001622856012501642       2016                        eng d00aTracing the architecture of caffeic acid phenethyl ester cocrystals: studies on crystal structure, solubility, and bioavailability implications0 aTracing the architecture of caffeic acid phenethyl ester cocryst  cOCT  a5710-57160 v163 a<p>Caffeic acid phenethyl ester (CAPE) is a polyphenolic active compound present in popular apiproduct, "propolis", obtained from beehives, Though it has broad therapeutic capability, the bioavailability of CAPE is limited due to poor solubility. In this study, we report novel cocrystals of CAPE engineered using coformers such as caffeine (CAP), isonicotinamide (INIC), and nicotinamide (NIC) with enhanced solubility and bioavailability of CAPE. The cocrystals were prepared by microwave-assisted cocrystallization and characterized using PXRD, DSC, and Raman spectroscopy. PXRD and DSC confirm the successful formation and phase purity of CAPE-CAF, CAPE-INIC, and CAPE-NIC cocrystals. Raman spectra of CAPE cocrystals complement these results in confirming the formation of novel crystalline phases. CAPE-NIC cocrystal was further subjected X-ray crystallography to understand its molecular arrangement and hydrogen bonding in the crystal structure. The CAPE-NIC cocrystal structure is found to be stabilized by a rare 1,2-benzenediol-amide heterosynthon. Cocrystallization of CAPE with NIC improved its aqueous solubility and pharmacokinetic profile, thereby demonstrating a 2.76-fold escalation in bioavailability.</p>1 aKetkar, Sameer1 aPagire, Sudhir, K.1 aGoud, Rajesh1 aMahadik, Kakasaheb, R.1 aNangia, Ashwini1 aParadkar, Anant  uhttp://library.ncl.res.in/content/tracing-architecture-caffeic-acid-phenethyl-ester-cocrystals-studies-crystal-structure02818nas a2200241   4500008004100000022001400041245009100055210006900146260000900215300001400224490000700238520200900245653002302254653003102277653002302308653001702331653002002348100002702368700002202395700002002417700002302437856011602460       2024                        eng d  a1543-838400aIn situ monitoring of competitive coformer exchange reaction by 1H MAS solid-state NMR0 aIn situ monitoring of competitive coformer exchange reaction by   cFEB   a1479-14890 v213 a<p>
	In a competitive coformer exchange reaction, a recent topic of interest in pharmaceutical research, the coformer in a pharmaceutical cocrystal is exchanged with another coformer that is expected to form a cocrystal that is more stable. There will be a competition between coformers to form the most stable product through the formation of hydrogen bonds. This will cause destabilization of the pharmaceutical products during processing or storage. Therefore, it is important to develop a mechanistic understanding of this transformation by monitoring each and every step of the reaction, employing a technique such as H-1 nuclear magnetic resonance (NMR). In this study, an in situ monitoring of a coformer exchange reaction is carried out by H-1 magic angle spinning (MAS) solid-state NMR (SSNMR) at a spinning frequency of 60 kHz. The changes in caffeine maleic acid cocrystals on addition of glutaric acid and caffeine glutaric cocrystals on addition of maleic acid were monitored. In all of the reactions, it has been observed that caffeine glutaric acid Form I is formed. When glutaric acid was added to 2:1 caffeine maleic acid, the formation of metastable 1:1 caffeine glutaric acid Form I was observed at the start of the experiment, indicating that the centrifugal pressure is enough for the formation. The difference in the end product of the reactions with a similar reaction pathway of 1:1 and 2:1 reactant stoichiometry indicates that a complete replacement of maleic acid has occurred only in the 1:1 stoichiometry of the reactants. The polymorphic transition of caffeine glutaric acid Form II to Form I at higher temperatures was a crucial reason that triggered the exchange of glutaric acid with maleic acid in the reaction of caffeine glutaric acid and maleic acid. Our results are novel since the new reaction pathways in competitive coformer exchange reactions enabled understanding the remarkable role of stoichiometry, polymorphism, temperature, and centrifugal pressure.</p>
10acaffeine cocrystal10acoformer exchange reaction10ain situ monitoring10apolymorphism10aSolid-state NMR1 aHareendran, Chaithanya1 aAlsirawan, Bashir1 aParadkar, Anant1 aAjithkumar, T., G.  uhttp://library.ncl.res.in/content/situ-monitoring-competitive-coformer-exchange-reaction-1h-mas-solid-state-nmr